Information is
available regarding the presence of Aedes albopictus in several municipalities
of the State of Amazonas. Specimens of this mosquito species have now, for the
first time, been collected from an urban area of the municipality of Manaus,
Amazonas, Brazil.

Keywords: Aedes.
Dengue. Geographic distribution. Aedes albopictus.

Originating from
Asia, where is it is an important vector for arboviruses, Aedes (Stegomyia)
albopictus (Skuse, 1894) became increasingly dispersed to other parts of
the world from 1980 onwards.2 It was found in the Americas for the
first time in 1985 and in Brazil in May 1986.1 This species has become
disseminated throughout Brazil, and has been found in various Brazilian states.2

In the State of
Amazonas, it was found for the first time in June 1996, specifically in the
immediate vicinity of Tabatinga (Figure), according to information
from the Fundação Nacional de Saúde - FUNASA (National Health Foundation)and
the Secretaria de Estado de Saúde do Amazonas - SUSAM (Amazonas State Health
Department). It was temporarily eliminated from that locality. Since then, an
entomological surveillance service for this species has been implemented, with
the use of larval traps installed in different locations within the city of
Letícia, on the frontier between Brazil and Colombia.5 Nonetheless,
in 1997 this species was again found both in Tabatinga and in the District of
Letícia.5

Today, the dispersion
of Ae. albopictus is affecting nine municipalities (Figure),
including Manaus, where its occurrence has now for the first time been recorded.
This comes from the information that an adult of Ae. albopictus was caught
on August 5, 2002, outside the Fundação de Medicina Tropical do Amazonas (Foundation
of Tropical Medicine of Amazonas), by an employee.

On August 15, 2002,
a search was undertaken for adults and immature forms around that area. Two
specimens were caught while feeding on blood from one of the collectors. From
this material, egg-laying was achieved. With the emergence of larvae, a second
generation was obtained. Since no natural occurrence of immature forms was found
during that search, receptacles were set out on September 3, 2002, to serve
as larval traps in the area where the adults had been collected. From this,
it was possible to record egg-laying and the emergence of larvae, pupation and
the adult form.

Although this species
has not yet been implicated as a vector for arboviruses in Brazil, it could
become a bridge between the forest and urban cycles of yellow fever or other
arboviruses, because of its capacity for adaptation to different environments.2
According to the few studies made in relation to its progressive dispersion,
Ae. albopictus has demonstrated a high capability for utilizing artificial
breeding areas within Brazilian territory, without abandoning natural ecotopes.2
Its epidemiological importance in the transmission of the dengue virus is recognized
in rural and urban areas in Asia, as well as its participation in the transmission
of Asian encephalitis.4

Even though it
is not yet clear what effect the presence of Ae. albopictus may have
on the dynamics of the transmission of the dengue virus in the Americas, its
interaction with Aedes aegypti needs attention, since both are species
that essentially develop within the same artificial breeding areas of rural,
urban and peripherally urban environments.3 Their competence as vectors
for transmitting diseases like dengue, yellow fever and Venezuelan equine encephalitis
have been proven under laboratory conditions.3 The risk of urban
epidemics increases with increased mosquito population density and wider distribution.
This is especially so in relation to the urban areas bordering rural areas where
sporadic cases of forest yellow fever are already occurring. The movement of
people infected with the yellow fever virus from rural to urban areas further
increases this risk.3 Thus, there is a need for vigilant monitoring
of how the presence of Ae. albopictus evolves under the new conditions
that it is subjected to in the neotropical region, and how it coexists with
Aedes aegypti.